How to catch rake task exit status in another rake task

Question

Problem

I have something like this:

task :fail do
  exit 111
end

task :run_fail_and_succeed do
  begin
    Rake::Task['knapsack:fail'].invoke
  rescue
    exit 0
  end
end

I would like to run task :fail and handle it's exit status. Than exit with 0. How can I do that?

Notes:

1. It can't be asynchronous / parallel / run in a background. :fail must finish before :run_fail_and_succeed.
2. It would be nice not only to exit with 0, but really handle this status code, so I could do different things based on it's value

Answer 1

rescue with a specific type of exception type. In your case, this should be SystemExit. Then you can check the fields associated with that exception.

task :run_fail_and_succeed do
  begin
    Rake::Task['knapsack:fail'].invoke
  rescue SystemExit => e
    puts e.status #=> 111
    # now you can handle your logic according to the exit status
  end
end